The "accidental millionaire", who allegedly fled the country with millions of dollars of Westpac's money after a bank error, has failed in a bid to have his bail conditions relaxed.

Leo Gao's application was rejected by Justice Paul Heath in the High Court at Rotorua on Wednesday who suppressed the nature of the application and prohibited any details relating to it being published.

Gao, 31, was dubbed the "accidental" and "runaway" millionaire after Westpac inadvertently credited his account with $10 million.

He had sought a $100,000 overdraft from the bank.

Gao left New Zealand for China after the money was deposited in his account.

He was arrested and taken back to New Zealand, where he is facing 16 charges of theft and two charges of money laundering in relation to $6.8 million.